We found this circuit in a 1964 Electronic Design. It provides 0.5 V signals from 4 kHz subcarriers. Transistors are from the era.
This circuit makes use of a mechanical delay line to produce the reverberation effect. This is a...
This circuit was found in an American documentation from 1975. The components of the time can no...
The oscillator circuit is an ICM7556, the dual CMOS version of the 555. The frequency depends on...